Polyvinyl alcohol spinning solution and fibers prepared therefrom



United States Patent PULYVINYL ALCGHOIL SPKNNENG SQLUTKON AND FillERPREPARED THEREFRGM Teruo Sada and Sadamaru Miyazalri, Kurashiki,.i'apan, assignors to Kurashilri Rayon (10., Ltd, Okayama, Japan, acorporation of Japan No Drawing. Filed May 23, 1961, Ser. No. 111,934Claims priority, application Japan, May 27, 1960, 35/25,439 6 (Ilaims.(Cl. 260-414) The present invention relates to the production of fibersof polyvinyl alcohol and is more particularly concerned with a novelspinning solution from which polyvinyl alcohol fibers of improvedcharacteristics can be produced.

Ordinary polyvinyl alcohol fibers do not exhibit good dyeability andmany proposals have been made for improving the dyeing properties ofpolyvinyl alcohol fibers. Many of these prior proposals for improvingthe dyeability of fibers of polyvinyl alcohol involve difiiculties,however, in their industrialization and they are, therefore, of limitedutility from a practical standpoint.

It is an object of this invention to provide a novel process forproducing polyvinyl alcohol fibers of improved dyeability.

It is another object of the invention to provide means for producingfibers of the character indicated which avoids the disadvantages anddrawbacks of prior proposals.

It is a further object of the invention to provide means readily adaptedto commercial polyvinyl alcohol fiber producing practices which permitspolyvinyl alcohol fibers of improved dyeability to be producedeconomically and Without complex operating procedures or reactions.

In accordance with the invention, polyvinyl alcohol fibers are producedfrom a polyvinyl alcohol spinning solution containing glucose or awater-soluble derivative of glucose.

It is a feature of this invention that the use of a polyvinyl alcoholspinning solution containing glucose or one of its Water-solublederivatives permits polyvinyl alcohol fibers of excellent dyeability tobe produced economically and efiiciently and at low cost.

It is a further feature of the invention that fibers spun from aspinning solution of the character indicated are transparent after wetspinning and even after they have subsequently been subjected to anafter-treatment, e.g. a heat treatment.

Other objects and features of the invention will be apparent from thefollowing detailed description, with particular reference toillustrative tion.

In order to illustrate the characteristic features of this invention,there were prepared a series of aqueous polyvinyl alcohol spinningsolutions. Each aqueous solution was prepared from polyvinyl alcoholhaving an average degree of polymerization of 1700 and in each solutionwas incorporated commercial glucose. The concentration of the polyvinylalcohol had a constant value of 15% in each solution but the amounts ofglucose were varied as follows: solution (1), 0% (control), solution(2), solution (3), 20%, solution (3'), 20%, and solution (4), 30%, thepercentages being based on the amount of polyvinyl alcohol. The spinningsolutions thus prepared were spun in a coagulation bath consisting of asaturated solution of Glaubers salt at 45 C. in accordance withconventional techniques, employing an immersion length of 1.5 meters, atake-up speed of 10 meters/min, and roller drawing of 300%. The fibersthus spun were subsequently dried in an air bath held at 180 C. Thefibers embodiments of the invenfrom solution (3) were also drawn 50% inair held at 230 C. The fibers were then subjected to heat treatmentsaliases Patented Apr. 20, 1905 for 30 seconds in an air bath held at 235C., and they were formalized at 70 C. for an hour in a formalizingsolution consisting of 5% formaldehyde, 15% sulfuric acid, and 15 sodiumsulfate. The strength, the elongation, the shrinkage in boiling Water,the dye absorption (Congo red 2%, Na SO 10%, bath ratio 50:1, C., 1hour) and the depth of the dye shade of the dyed fibers were measured.The depth of shade was measured with varying concentrations of Congored, Na ,SO 10%, bath ratio 50:1 at 80 C., 2 hours. The value of thedepth of shade is expressed in terms of K/S at a dye absorption of 10mg./ g. of the material to be dyed, using the formula (1 K /S R m whereR00 is the coeificient of reflection for the wav length 520 mu. Theresults are tabulated in the following table:

From the foregoing results, it will be seen that conspicuousimprovements in the dyeing absorption and in the depth of shade of thedyed fibers are apparent. While the tests show that with increasingamounts of glucose the strength tends to decrease somewhat, when thesame manufacturing steps are used, it will also be seen from the testson the fibers from solution (3) that any decrease of strength can befully compensated for by drawing. On the other hand, variations in theamount of glucose added do not significantly affect the improvedelongation and the shrink-resistance in water which are achieved. Thefibers from solution l) were opaque, just as in thecase of ordinaryVinylon fibers. The fibers produced from solution (2), however, weregenerally transparent, and conspicuously transparent fibers wereproduced from solutions (3) and (4), the transparency of the fibers fromsolution (3) lying between those from solutions (2) and (3). Thisactivity of glucose in giving the fibers a transparent appearance isthought to be related to the marked improvement in the depth of shade ofthe dyed fibers which is observed.

While glucose has been referred to above, the new results provided bythis invention can also be obtained by the use of water-solublederivatives of glucose, e.g. alkyl and acetyl derivatives of glucose,such as monomethyl glucose, dimethyl, glucose, trimethyl glucose,monoacetyl glucose, diacetyl glucose, triacetyl glucose, fi-glucosan,and the like.

The invention will be further understood from the following specificexamples of practical application. However, it will be understood thatthese examples are not to be construed as limiting the scope of thepresent invention in any manner. In these examples, all parts are byweight, unless otherwise indicated.

Example 1 taining 4% formaldehyde and 16% sulfuric acid. The

An aqueous solution containing 15% polyvinyl alcohol having an averagedegree of polymerization of 1700 and 10% glucose (based on the amount ofpolyvinyl alcohol) was wet spun by conventional techniques into asaturated aqueous solution of Glaubers salt maintained at 45 C., and thefibers produced was roller drawn by 400%, then heat-dried in hot air at180 C. These fibers was subjected to heat-treatment for 2 minutes at 210C. in super-heated steam at 1 atmosphere gage pressure, and they werebenzalized at 60 C. for 1 hour by immersion in an aqueous solutioncontaining 1% benzaldehyde, 0.3% sodium dibutyl naphthalene sulfonate,and 2% sulfuric acid. The thus obtained fibers were transparent, whereasfibers produced under identical conditions, but from a spinning solutionto which no glucose was added, were opaque, and the former were dyed fardeeper than the latter when dyed with Celliton Fast Blue FFR.

Example 3 An aqueous solution containing 14% polyvinyl alcohol having anaverage degree of polymerization of 1600 and 30% glucose (based on theamount of polyvinyl alcohol) was wet spun in a saturated aqueoussolution of Glaubers salt maintained at 50 C., and the fibers producedwere dried with-out further handling. These fibers were heat-drawn by700% in air at 230 C., then shrunk 15% in air at 235 C. The fibers weresubsequently acetalized at 60 C. for 2 hours in an aqueous solutioncontaining 0.5% formaldehyde, 2% fi-cyclohexyl aminobutylaldehyde, 15%sulfuric acid, and 10% sodium sulfate. These fibers exhibited far betterdepth of shade than control fibers produced under the same conditions,but from a spinning solution to which no glucose was added, when theywere dyed for 1 hour at 80 C. with 2% acid dye, Acid Scarlet 3R, 1%sulfuric acid (bath ratio, 5011).

Example 4 An aqueous solution was prepared from aminoacetalizedpolyvinyl alcohol which was 30% acetalized with fl-cyclohexylaminobutylaldehyde and from polyvinyl alcohol having an average degreeof polymerization of 1700, the quantities of the two compounds beingchosen to provide an average degree of amino-acetalation of 1%, and aconcentration of total polyvinyl compounds of 15%. To this solution wasadded glucose in the amount of 20% based on the total quantity ofpolyvinyl compounds. Thisaqueous solution was then conventionally wetspun into a saturated aqueous solution 'of Glaubers salt maintained at45 C., and the fibers were roller-drawn by 200%, and heat-dried. Thesefibers were then heat-drawn by 200% in air at 225 C., subjected toheat-treatment at 230 C. at constant length, and subsequently benzalizedfor 1 hour at 60 C.,in an aqueous solution containing 2% henzaldehyde,40% methanol, and 10% sulfuric acid. These fibers surpassed in depth ofshade control fibers produced without the use of glucose when the twofibers were dyed at 80 C. for 1 hour in a dyeing bath having a bathration of 50:1 and containing 2% Acid Scarlet 3R, and 1% acetic acid. Itwas noted that both fibers had absorbed the dye in the dyeing bath.

E xample5 An aqueous solution containing 16% polyvinyl alcohol having anaverage degree of polymerization of 1700 and 25% glucose (based on theamount of polyvinyl alcohol) was wet spun into a saturated aqueoussolution of Glaubers salt at 50 C. The fibers obtained was subjected toheat-treatment for 2 hours in saturated Glaubers salt maintained at C.,and they ere then formalized as described in Example 1. These fiberswere highly transparent, and exhibited better dyeability than thecontrol fibers produced without the presence of glucose in the spinningsolution.

Example 6 An aqueous solution containing 13% polyvinyl alcohol having anaverage degree of polymerization of 2000 and 20% trimethyl glucose(based on the amount of polyvinyl alcohol) was wet spun by extruding itinto a coagulation bath containing 350 g./liter of sodium sulfate heldat 55 C. The fibers obtained were subjected to heat-treatment in an airbath maintained at 230 C. at constant length, and they were subsequentlyformalized at 65 C. for 1 hour in an aqueous solution containing 5%formaldehyde, 20% sulfuric acid, and 5% sodium sulfate.

These fibers, in comparison with the control fibers produced without theuse of glucose, had a cross-section which was almost circular, owing tothe marked improvement in their solidity, and they exhibited atransparent appearance and excellent dyeability.

Example 7 An aqueous solution containing 13% polyvinyl alcohol having anaverage degree of polymerization of 1700, 35% diacetyl glucose (based onthe amount of polyvinyl alcohol), and 1% blue pigment (based on theamount 01: polyvinyl alcohol), was wet spun into a saturated aqueoussolution of Glaubers salt held at 45 C., and the fibers were subjectedto heat-treatment in air at 220 C., and they were then formalized at 70C. for 1 hour in an aqueous solution containing 5% formaldehyde, 1 5%sulfuric acid, and 15% sodium sulfate. These fibers had an extremelydeep color and exhibited good coloration when dyed in comparison withthe control fibers produced Without the use of glucose.

The conditions and. relative relationships set forth in the examples arethose preferred but it will be understood that other conditions andrelationships may be used within the scope of the invention. Forexample, the amount of glucose or glucose derivative specified in theexamples of 10 to 35 percent based on the weight of the total polymer ispreferred, these percentages being based on the dry weight of theadditive. In general, unless otherwise indicated, conventionaloperations and techniques are suitably employed.

Thus, any polyvinyl alcohol suitable for spinning into fibers may beused. Typical polyvinyl alcohols which can be suitably used aredescribed, forexample, in Cline et al. US. Patent 2,636,803. Similarly,mixed spinning solutions may be prepared containing polyvinyl alcohol incombination with other polymers, e.g. a nitrogen-containing polyvinylalcohol, as the polymer components, as described, for example in theco-pending applicationrof Matsubayashi et 211., Serial No. 42,998, filedJuly 15, 1960, now United States Patent No. 3,137,673. The spinning ofthe fibers from the spinning solution containing glucose or glucosederivatives in accordance with the invention is effected by conventionalWet-spinning techniques.

Thus, the solutions are spun to form fibers, for example, inconventional manner by extruding the solution through. small holes in aspinning jet into a medium elfective to remove water therefrom. In wetspinning processes the medium can, for example, be a concentratedaqueous solution of a coagulating salt such as sodium sulfate orammonium sulfate, while in dry spinning techniques air or an inert gassuch as nitrogen is employed.

Suitable spinning conditions for producing fibers from the spinningsolutions of this invention are described, for example, in U.S. Patent2,642,333 as well as in Cline et al. US. Patent 2,636,803 and Osugi etal. US. Patent 2,906,594.

The fibers may suitably be stretched and heat treated in accordance withconventional techniques as illustrated, for example, in US. Patents2,636,803, 2,636,804 and 2,906,594. Thus, the fibers are suitablystretched to a draw ratio of about 2:1 to 12:1 during or after spinning.For Wet spun filaments, the stretching can be carried out directly afterspinning while the fibers are wet at room temperature up to 100 C. to adraw ratio of about 5:1. For stretching to higher draw ratios, it ispreferred to conduct the stretching in a heated medium such as air at100250 C.

Heat treatment is usually carried out by heating the fibers in a mediumsuch as air at 2l0-250 C. for 2 seconds to 5 minutes.

Acetalization is conveniently carried out in conventional manner in anaqueous solution containing 02-10% aldehyde, 5*20% sulfuric acid and-25% sodium sulfate or ammonium sulfate at temperatures of 4080 C. fortimes ranging from a few minutes, e.g. 10' minutes, to several hours,eg, hours.

The polymers contained in the solutions of this invention are similarlyformed into other shapes such as films by conventional techniques. Thus,films are suitably produced by the procedure described, for example, inIzard et al. US. 2,236,061 and in Herrmann et al. US. Patent 2,837,770.

It will also be understood that various changes and modifications inaddition to those indicated above may be made in the embodiments hereindescribed without departing from the scope of the invention as definedin the appended claims. It is intended, therefore, that all mattercontained in the foregoing description shall be interpreted asillustrative only and not as limitative of the invention.

We claim:

1. A spinning solution efii'ective to form polyvinyl alcohol fibers ofimproved dyeing characteristics which consists essentially of an aqueoussolution of polyvinyl alcohol in combination with a member selected fromthe group consisting of glucose, monomethyl glucose, di-

methyl glucose, trimethyl glucose, monoacetyl glucose,

diacetyl glucose, triacetyl glucose, and beta-glucosan, said memberbeing present in said solution in an amount of from to 35% based on theweight of said polyvinyl 5 alcohol in said solution.

2. A process of forming polyvinyl alcohol fibers having improved dyeingcharacteristics which comprises introducing into a coagulation bath aspinning solution which consists essentially of an aqueous solution ofpolyvinyl alcohol in combination with a member selected from the groupconsisting of glucose, monomethyl glucose, dimethyl glucose, trimethylglucose, monoacetyl glucose, diacetyl glucose, triacetyl glucose andbeta-glucosan, said member being present in said solution in an amountof from 10% to 35 based on the weight of said polyvinyl alcohol in saidsolution.

3. A process according to claim 2, wherein said member is glucose.

4. A process according to claim 2, wherein said mem- 2 ber is trimethylglucose.

5. A process according to claim 2, wherein said member is diacetylglucose.

6. Polyvinyl alcohol fibers of improved dyeing characteristicsconsisting essentially of polyvinyl alcohol and a member selected fromthe group consisting of glucose, monomethyl glucose, dimethyl glucose,trimethyl glucose, monoacetyl glucose, diacetyl glucose, triacetylglucose, and beta-glucosan, said member being present in said fiber inan amount of 10% to based on the weight of said 3 polyvinyl alcohol insaid fiber.

References Cited by the Examiner UNITED STATES PATENTS 2,239,718 4/41Gizard 264-485 35 2,265,283 12/41 Hermann et a1. 260--91.3

2,457,357 12/48 Fenn 26017.4

2,595,276 5/52 Lowry 26017.4

2,716,049 8/55 Latour 260--91.3

LEON J. BERCOVITZ, Primary Examiner. JAMES A. SEIDLECK, Examiner.

1. A SPINNING SOLUTION EFFECTIVE TO FORM POLYVINYL ALCOHOL FIBERS OFIMPROVED DYEING CHARACTERISTICS WHICH CONSISTS ESSENTIALLY OF AN AQUEOUSSOLUTION OF POLYVINYL ALCOHOL IN COMBINATION WITH A MEMBER SELECTED FROMTHE GROUP CONSISTING OF GLUCOSE, NONOMETHYL GLUCOSE, DIMETHYL GLUCOSE,TRIMETHYL GLUCOSE, MONOACETYL GLUCOSE, DIACETYL GLUCOSE, TRIACETYLGLUCOSE, AND BETA-GLUCOSAN, SAID MEMBER BEING PRESENT IN SAID SOLUTIONIN AN AMOUNT OF FROM 10% TO 35% BASED ON THE WEIGHT OF SAID POLYVINYLALCOHOL IN SAID SOLUTION.